bone

bone

[bōn]

1. the hard, rigid form of connective tissue constituting most of the skeleton of vertebrates, composed chiefly of calcium salts.

2. any distinct piece of the skeleton of the body. See anatomic Table of Bones in the Appendices for regional and alphabetical listings of bones, and see color plates 1 and 2. Called also os. adj., adj bo´ny.

There are 206 separate bones in the human body. Collectively they form the skeletal system, a structure bound together by ligaments at the joints and set in motion by the muscles, which are secured to the bones by means of tendons. Bones, ligaments, muscles, and tendons are the tissues of the body responsible for supporting and moving the body.

Some bones have a chiefly protective function. An example is the skull, which encloses the brain, the back of the eyeball, and the inner ear. Some, such as the pelvis, are mainly supporting structures. Other bones, such as the jaw and the bones of the fingers, are concerned chiefly with movement. The bone marrow in the center manufactures blood cells. The bones themselves act as a storehouse of calcium, which must be maintained at a certain level in the blood for the body's normal chemical functioning.

Structure and Composition. Bone is not uniform in structure but is composed of several layers of different materials. The outermost layer, the periosteum, is a thin, tough membrane of fibrous tissue. It gives support to the tendons that secure the muscle to the bone and also serves as a protective sheath. This membrane encloses all bones completely except at the joints where there is a layer of cartilage. Beneath the periosteum lie the dense, hard layers of bone tissue called compact bone. Its composition is fibrous rather than solid and it gives bone its resiliency. Encased within these layers is the tissue that makes up most of the volume of bone, called cancellous or spongy bone because it contains little hollows like those of a sponge. The innermost portion of the bone is a hollow cavity containing marrow. Blood vessels course through every layer of bone, carrying nutritive elements, oxygen, and other products. Bone tissue also contains a large number of nerves. The basic chemical in bone, which gives bone its hardness and strength, is calcium phosphate.

Development. Cartilage forms the major part of bone in the very young; this accounts for the great flexibility and resiliency of the infant skeleton. Gradually, calcium phosphate collects in the cartilage, and it becomes harder and more brittle. Some of the cartilage cells break loose, so that channels develop in the bone shaft. Blood vessels enter the channels, bearing with them small cells of connective tissue, some of which become osteoblasts, cells that form true bone. The osteoblasts enter the hardened cartilage, forming layers of hard, firm bone. Other cells, called osteoclasts, work to tear down old or excess bone structure, allowing the osteoblasts to rebuild with new bone. This renewal continues throughout life, although it slows down with age.

Cartilage formation and the subsequent replacement of cartilage by hard material is the mechanism by which bones grow in size. During the period of bone growth, cartilage grows over the hardened portion of bone. In time, this layer of cartilage hardens as calcium phosphate is added, and a fresh layer grows over it, and it too hardens. The process continues until the body reaches full growth. Long bones grow in length because of special cross-sectional layers of cartilage located near the flared ends of the bone. These harden and new cartilage is produced by the same process as previously described.

Bone Disorders. fracture, a break in the bone, is the most common injury to the bone; it may be closed, with no break in the skin, or open, with penetration of the skin and exposure of portions of the broken bone. osteoporosis is excessive brittleness and porosity of bone in the aged. osteomyelitis is a bone infection similar to a boil on the skin, but much more serious because blood supply to bone is less exquisite than that to other body organs and bone metabolizes more slowly, so that the infection can destroy the bone and invade other body tissues. osteomalacia is the term used for rickets when it occurs in adults. In these diseases there is softening of the bones, due to inadequate concentration of calcium or phosphorus in the body. The usual cause is deficiency of vitamin D, which is required for utilization of calcium and phosphorus by the body. In osteitis fibrosa cystica, bone is replaced by fibrous tissue because of abnormal calcium metabolism. The condition usually is due to overactivity of the parathyroid glands. osteoma refers to abnormal new growth, either benign or malignant, of the tissue of the bones. Although it is not common, it may occur in any of the bones of the body, and at any age.

alveolar bone the thin layer of bone making up the bony processes of the maxilla and mandible, surrounding and containing the teeth; it is pierced by many small blood vessels, lymphatic vessels, and nerves.

cortical bone the compact bone of the shaft of a bone that surrounds the marrow cavity.

cranial b's the bones that constitute the cranium, including the occipital, sphenoid, temporal, parietal, frontal, ethmoid, lacrimal, and nasal bones, the inferior nasal concha, and the vomer. Some authorities also include the maxilla, zygomatic bone, and palatine bone. See anatomic Table of Bones in the Appendices.

ethmoid bone the sievelike bone that forms a roof for the nasal fossae and part of the floor of the anterior cranial fossa. See anatomic Table of Bones in the Appendices.

facial b's the bones that form the skeleton of the face, including the hyoid, palatine, and zygomatic bones, the mandible, and the maxilla. Some authorities include the lacrimal bones, nasal bones, inferior nasal concha, and vomer and exclude the hyoid bone. See anatomic Table of Bones in the Appendices.

flat bone one whose thickness is slight, sometimes consisting of only a thin layer of compact bone, or of two layers with intervening cancellous bone and marrow; usually curved rather than flat.

frontal bone the bone at the anterior part of the skull. See anatomic Table of Bones in the Appendices.

hip bone the ilium, ischium, and pubis as a unit. See anatomic Table of Bones in the Appendices.

hyoid bone a horseshoe-shaped bone at the base of the tongue. See anatomic Table of Bones in the Appendices. Called also lingual bone.

incisive bone the portion of the maxilla bearing the incisors; developmentally, it is the premaxilla, which in humans later fuses with the maxilla, but in most other vertebrates persists as a separate bone.

zygomatic bone the quadrilateral bone that forms a cheek. See anatomic Table of Bones in the Appendices.

bone

(bōn), [TA]

A hard connective tissue consisting of cells embedded in a matrix of mineralized ground substance and collagen fibers. The fibers are impregnated with inorganic components, including crystals of calcium phosphate, such that using X-ray defraction, they are seen to be organized in a hydroxyapatite pattern (calcium phosphate is 85% by weight) as well as calcium carbonate (10%), and magnesium; by weight, bone is composed of 65-75% inorganic and 25-35% organic material; a portion of osseous tissue of definite shape and size, forming a part of the animal skeleton; in humans there are approximately 200 distinct bones in the skeleton, not including the auditory ossicles of the tympanic cavity or the sesamoid bones other than the two patellae. A bone is enveloped by a fibrous membrane, periosteum, that covers the bone's entire surface except for the articular cartilage. Beneath the periosteum is a dense layer, compact bone, and beneath that a cancellous layer, spongy bone. The core of a long bone is filled with marrow.

cortical bone the compact bone of the shaft of a bone that surrounds the marrow cavity.

cuboid bone a bone on the lateral side of the tarsus between the calcaneus and the fourth and fifth metatarsal bones.

cuneiform bone, intermediate the intermediate and smallest of the three wedge-shaped tarsal bones located medial to the cuboid and between the navicular and the first three metatarsal bones.

cuneiform bone, lateral the most lateral of the three wedge-shaped tarsal bones located medial to the cuboid and between the navicular and the first three metatarsal bones.

cuneiform bone, medial the medial and largest of the three wedge-shaped tarsal bones located medial to the cuboid and between the navicular and the first three metatarsal bones.

ethmoid bone the cubical bone located between the orbits and consisting of the lamina cribrosa, the lamina perpendicularis, and the paired lateral masses.

flat bone one whose thickness is slight, sometimes consisting of only a thin layer of compact bone, or of two layers with intervening cancellous bone and marrow; usually curved rather than flat.

frontal bone a single bone that closes the anterior part of the cranial cavity and forms the skeleton of the forehead; it is developed from two halves, the line of separation (the frontal suture) sometimes persisting in adult life.

funny bone the region of the median condyle of the humerus where it is crossed by the ulnar nerve.

hip bone the large bone in the hip, consisting of the ilium, the ischium, and the pubic bone.

hyoid bone a horseshoe-shaped bone at the base of the tongue, just superior to the thyroid cartilage.

incisive bone the portion of the maxilla bearing the incisors; developmentally, it is the premaxilla, which in humans later fuses with the maxilla, but in most other vertebrates persists as a separate bone.

lacrimal bone a thin scalelike bone at the anterior part of the medial wall of the orbit, articulating with the frontal and ethmoid bones and the maxilla and inferior nasal concha.

lamellar bone the normal type of adult bone, organized in layers (lamellae), which may be parallel (cancellous b.) or concentrically arranged (compact b.).

lingual bone hyoid b.

long bone a bone that has a longitudinal axis of considerable length, consisting of a body or shaft (the diaphysis) and an expanded portion (the epiphysis) at each end that is usually articular; typically found in the limbs.

lunate bone the bone in the proximal row of carpal bones lying between the scaphoid and triquetral bones.

metacarpal bones the five cylindrical bones of the hand (metacarpals), which articulate proximally with the bones of the wrist and distally with the proximal phalanges of the fingers; numbered from that articulating with the phalanx of the thumb to that articulating with the phalanx of the little finger.

metatarsal bones the five bones (metatarsals) extending from the ankle to the phalanges of the toes; numbered from the most medial articulating with the phalanx of the big toe to the most lateral articulating with the phalanx of the little toe.

nasal bone either of the two small, oblong bones that together form the bridge of the nose.

navicular bone the oval-shaped tarsal bone found between the talus and the three cuneiform bones.

occipital bone a single trapezoid-shaped bone at the posterior inferior part of the cranium, articulating with the two parietal and two temporal bones, the sphenoid bone, and the atlas; it contains a large opening, the foramen magnum.

palatine bone the irregularly shaped bone forming the posterior part of the hard palate, the lateral wall of the nasal fossa between the medial pterygoid plate and the maxilla, and the posterior part of the floor of the orbit.

parietal bone either of the two quadrilateral bones forming part of the superior and lateral surfaces of the skull, and joining each other in the midline at the sagittal suture.

pubic bone the anterior inferior part of the hip bone on either side, articulating with its fellow in the anterior midline at the pubic symphysis; it is a separate bone in early life.

rider's bone localized ossification of the inner aspect of the lower end of the tendon of the adductor muscle of the thigh; sometimes seen in horseback riders.

semilunar bone lunate b.

sesamoid bones numerous ovoid nodular bones, often small, usually found embedded within a tendon or joint capsule, principally in the hands and feet; two sesamoid bones, the fabella and patella, are associated with the knee.

tarsal bones the seven bones of the ankle (tarsus), including the calcaneus, the cuboid bone, the navicular bone, the talus, and the intermediate, lateral, and medial cuneiform bones.

temporal bone either of the two irregular bones forming part of the lateral surfaces and base of the skull, and containing the organs of hearing. It is divided anatomically into four parts: the mastoid, petrous, squamous, and tympanic parts.

zygomatic bone the quadrangular bone of the cheek, articulating with the frontal bone, the maxilla, the zygomatic process of the temporal bone, and the greater wing of the sphenoid bone.

bone

(bōn)

n.

1.

a. The dense, semirigid, porous, calcified connective tissue forming the major portion of the skeleton of most vertebrates. It consists of a dense organic matrix and an inorganic, mineral component.

b. Any of numerous anatomically distinct structures making up the skeleton of a vertebrate animal. There are more than 200 different bones in the human body.

c. A piece of bone.

2. bones

a. The skeleton.

b. The body: These old bones don't do much dancing anymore.

c. Mortal remains: His bones are buried up on the hill.

3. An animal structure or material, such as ivory, resembling bone.

4. Something made of bone or of material resembling bone, especially:

a. A piece of whalebone or similar material used as a corset stay.

b. bonesInformal Dice.

5. bones The fundamental plan or design, as of the plot of a book.

6.

a. bones Flat clappers made of bone or wood originally used by the end man in a minstrel show.

b. Bones(used with a sing. verb) The end man in a minstrel show.

7. Vulgar Slang The penis.

v.boned, boning, bones

v.tr.

1. To remove the bones from: bone a fish.

2. To stiffen (a piece of clothing) with stays, as of whalebone.

3. Vulgar Slang To have sexual intercourse with. Used especially of a man.

v.intr.

Vulgar Slang To have sexual intercourse.

bone

Etymology: AS, ban

1 the dense, hard, and somewhat flexible connective tissue constituting the framework of the human skeleton. It is composed of compact osseous tissue surrounding spongy cancellous tissue permeated by many blood vessels and nerves and enclosed in membranous periosteum.

2 any single element of the skeleton, such as a rib, the sternum, or the femur. Also called (Latin) os. See also connective tissue.

Structure of a long bone

bone

adjective Bony, osseous; referring to bone.

Anatomynoun A solid, rigid, ossified connective tissue forming an organ of the skeletal system; any of the 206 bones in the body.

Drug slangnoun A regional street term for:(1) Marijuana;(2) A large rock of crack cocaine.

bone

(bōn) [TA]

1. A hard connective tissue consisting of cells embedded in a matrix of mineralized ground substance and collagen fibers. The fibers are impregnated with a form of calcium phosphate similar to hydroxyapatite as well as with substantial quantities of carbonate, citrate, sodium, and magnesium; by weight, bone is composed of 75% inorganic material and 25% organic material.

2. A portion of osseous tissue of definite shape and size, forming a part of the animal skeleton; in human adults there are approximately 200 distinct bones in the skeleton, not including the auditory ossicles of the tympanic cavity or the sesamoid bones other than the two patellae. A bone is enveloped by a fibrous membrane, periosteum, that covers the bone's entire surface except for the articular cartilage. Beneath the periosteum is a denselayer, compact bone, and beneath that a cancellous layer, spongy bone. The core of a long bone is filled with marrow. Synonym(s): os [TA] .

2. A unit of the skeleton; the human skeleton has 206 bones. Bones surround and protect some vital organs, and give points of attachment for the muscles, serving as levers and making movement possible. In the embryo, the bones of the skull are first made of fibrous connective tissue, which is gradually replaced by bone matrix. The remainder of the skeleton is first made of hyaline cartilage, which is also replaced by bone matrix, beginning during the third month of gestation. The outer surface of a bone is compact bone, and the inner more porous portion is cancellous (spongy) bone. The shafts of long bones are made of compact bone that surrounds a marrow canal. Compact bone is made of haversian systems, which are precise arrangements of osteocytes, blood vessels, and lymphatics within the bony matrix. All of these contribute to the maintenance and repair of bone. The periosteum is the fibrous connective tissue membrane that covers a bone. It has blood vessels that enter the bone, and it provides a site of attachment for tendons and ligaments. Bones are classified according to shape as long, short, flat, or irregular. In the elderly, esp. women, osteoporosis may develop, a condition in which bones become brittle and break easily. See: illustration; skeleton for names of principal bones

alveolar bone

The bony tissue or process of the maxilla or mandible that supports the teeth.

cancellous bone

carpal bone

One of the eight wrist bones, which are aligned in two rows. The proximal row contains (from the thumb to the little finger) the scaphoid, lunate, triquetral, and pisiform bones. The distal row contains (from thumb to little finger) the trapezium, trapezoid, capitate, and hamate bones.

cartilage bone

A bone formed by endochondral ossification developing from the primary centers of bone formation. Synonym: endochondral bone

cavalry bone

collar bone

compact bone

The hard, dense bone made of haversian systems that forms the surface layer of all bones and the shafts of long bones, in contrast to spongy bone that forms the bulk of the short, flat, and irregular bones and the ends of long bones.

cotyloid bone

A bone that forms a part of the medial portion of the acetabulum during fetal development. It subsequently fuses with the pubis.

cranial bone

A bone of the skull or brain case.

cuboid bone

The outer bone of the instep bones of the foot that articulates posteriorly with the calcaneus and anteriorly with the fourth and fifth metatarsals.

cuneiform bone

One of the bones of the internal, middle, and external tarsus.

dermal bone

ear bone

endochondral bone

ethmoid bone

A complex thin-walled bone, roughly cuboidal in shape, located in the middle of the skull above the nasal cavities and below the anterior fossa of the cranial cavity. Its flat upper surface is the cribriform plate, which forms much of the roof of the nasal cavities; its upper surface has a midline bony keel that projects up into the cranial cavity and on both sides of which are perforated valleys through which the olfactory nerves project up from the olfactory epithelium. In the midline under the cribriform plate is a mirror-image (to the crista galli) keel, the perpendicular plate, which projects down between the nasal cavities as part of the bony nasal septum. The right and left sides of the ethmoid bone are the ethmoidal labyrinths, composed of ethmoidal air cells; the inner surfaces of the labyrinths form the middle nasal conchae, while the lateral surfaces form the orbital plates, which are part of the mosaic of bones that form the inner walls of the orbits.

frontal bone

The forehead bone.

funny bone

A colloquial term for the groove along the inner back side of the elbow (behind and underneath the medial epicondyle of the humerus) in which the ulnar nerve runs. Pressure on the groove compresses the ulnar nerve, producing a tingling discomfort on the inside of the forearm as well as the 4th and 5th fingers.

greater multangular bone

The first or outermost of the distal row of carpal bones. Synonym: trapezium

hamate bone

The most medial wrist (carpal) bone in the distal row. It has a hooked process on its palmar side. The hamate articulates with the 4th and 5th metacarpals. Synonym: hamatum; os hamatum; unciform bone

heel bone

hip bone

hyoid bone

The horseshoe-shaped bone at the base of the tongue. It is mobile and its ends hang by the stylohyoid ligaments from the styloid process on each side of the base of the skull. The hyoid bone is suspended by many muscles (the hyoid muscles): the suprahyoid muscles (geniohyoid, mylohyoid, digastric, and hyoglossus) attach the hyoid bone to the mandible and the floor of the mouth; the infrahyoid muscles (omohyoid, sternohyoid, and thyrohyoid) attach it to the larynx and the thoracic cage. The hyoid bone anchors and moves with the jaw, tongue, pharynx, and larynx.

See: illustration

incisive bone

The part of the maxilla bearing the incisor teeth.

innominate bone

The hip bone or os coxae, composed of the ilium, ischium, and pubis. It is united with the sacrum and coccyx by ligaments to form the pelvis. Synonym: pelvic bone; os coxae.

marble bone

metatarsal bone

Any of the bones of the metatarsus.

See: foot for illus.

membrane bone

Bone formed within embryonic fibrous connective tissue, in which fibroblasts differentiate into osteoblasts. Such bone is formed without a cartilage model and includes the bones of the face and cranium. Synonym: dermal bone; intramembraneous bone

parietal bone

pelvic bone

perichondrial bone

Bone formed beneath the perichondrium.

periosteal bone

Bone formed by osteoblasts of the periosteum.

ping pong bone

A thin shell of osseous tissue covering a giant-cell sarcoma in a bone.

pubic bone

The lower anterior part of the innominate bone. It is a separate bone at birth; it begins to fuse with the ischium by age 8, and it is fully fused with the ischium and ilium by 16-18 years of age. Synonym: os pubis

replacement bone

Any bone that develops within cartilage.

rider's bone

Ossification of the distal end of the adductor muscles of the thigh, as may be seen in horseback riders. Synonym: cavalry bone

sesamoid bone

Soemmering's bone

sphenoid bone

The large bone at the base of the skull that has the ethmoid bone in front of it, the occipital bone behind it, and the parietal and temporal bones at the sides. It is shaped like a large moth. Its two broad, curved wings form the front walls of the middle cranial fossae, and its two “tails, ” the pterygoid processes, which hang in front of the neurocranium in the pterygoid fossa behind the facial skeleton. Between the wings, in the center of the body of the sphenoid bone, there is a deep, concave pocket (the sella turcica), in which the pituitary gland lies.

wormian bone

woven bone

zygomatic bone

The cheekbone; the bone on either side of the face below the eye. Synonym: malar bone

illustration

bone

The principle skeletal structural material of the body. Bone consists of a protein, type 1 COLLAGEN scaffolding impregnated with calcium phosphate hydroxyapatite crystals. As bone grows new bone is laid down immediately under the bone-covering membrane (periostium) and is absorbed from the inner surface. Oestrogens inhibit periosteal bone formation in women but promotes internal bone formation; androgens promote periosteal bone formation in males. The marrow of the flat bones are the sites of blood production. See also BONE MARROW.

Fig. 77 Bone . The shaded areas are lacunae occupied by osteoblasts.

bone

the skeletal substance of vertebrate animals, consisting largely of calcium and phosphate which make up 60% of the weight and gives it hardness. This ‘bone salt’, together with large numbers of COLLAGEN fibres, forms a matrix in which cells (OSTEOBLASTS) are distributed, and these are connected by delicate channels (canaliculi). Larger channels carry blood vessels and nerves (Haversian canals) and the cells are arranged concentrically around them. Haversian bone is found in the shafts of limb bones and is compact, whilst spongy bone is found at the ephiphyses (ends of bone).

calcium

the most abundant mineral in the body. Combined with phosphorus in bones and teeth. The two together represent about 75% of the body's total mineral content. ionized calcium ( Ca2+), about 1% of the 1200 mg total calcium, plays a crucial role in all physiological functions including muscle action, blood clotting, transmission of nerve impulses, activation of several enzymes, synthesis of the active form of vitamin D, and transport across all cell membranes; its level in the blood is regulated by exchange with Ca in bone and by variation in renal excretion, under hormonal influences. Calcium is one of the most frequently inadequate nutrients in the diet of both athletes and non-athletes. Female dancers, gymnasts and endurance competitors are among those most prone to calcium dietary insufficiency. See also bone, coagulation, excitation-contraction coupling, hormones(tableTable 1), micronutrients, minerals, parathyroid gland, tetany.

Within insertion of flexor hallucis longus tendon, adjacent to plantar area of hallux interphalangeal joint

bone

(bōn) [TA]

Hard connective tissue consisting of cells embedded in a matrix of mineralized ground substance and collagen fibers. Fibers are impregnated with inorganic components, including crystals of calcium phosphate, such that using X-ray defraction, they are seen to be organized in a hydroxyapatite pattern (calcium phosphate is 85% by weight) as well as calcium carbonate (10%), and magnesium; by weight, bone is composed of 65-75% inorganic and 25-35% organic material; humans have approximately 200 distinct bones in the skeleton, not including the auditory ossicles of the tympanic cavity or the sesamoid bones other than the two patellae.

[A.S. bān]

bone,

n1. the material of the skeletons of the tissue composing bones. n2. dense, hard, and slightly elastic connective tissue in which the fibers are impregnated with a form of calcium phosphate similar to hydroxyapatite. 3. the bones of the human skeleton. n4. a single element of the skeleton such as a rib or femur.

bone, alveolar

n the specialized bone structure that contains the alveoli or sockets of the teeth and supports the teeth.

bone, alveolar, architecture,

n the structural pattern of the alveolar bone and its subjacent latticework of supporting bone. The alveolar bone is thin and compact adjacent to the periodontal ligament. The trabecular bone connects and reinforces the individual alveoli. The architecture of a bone is the result of functional stimuli to that bone; the stimuli vary according to type, intensity, and duration.

bone, alveolar, metabolism,

n the metabolic activity occurring within alveolar bone, which is generally slower than that occurring within metaphyseal bone but more rapid than that of diaphyseal bone.

bone apposition,

n See bone deposition.

bone augmentation,

n a procedure used to build or enhance bone. It refers to either bone grafting or bone growing. Bone augmentation materials are classified as osseous, in which bone or bony substitutes are used to form new bone, or osseous conductive, in which these materials provide a platform for regeneration without taking part in actual bone formation.

bone, basal,

n the part of the mandible and maxilla from which the alveolar process develops.

bone, bundle,

n the bone forming the immediate bone attachment of the numerous bundles of collagen fibers of the periodontal ligament that have been incorporated into the bone.

bone bur,

n a drill designed to cut into bone.

bone, cadaver,

n bone that has been donated for medical purposes from one person to another; used especially in bone grafting procedures. See also allogenic and allografts.

bone calcium content,

n the amount of calcium stored in bone tissue. Plasma calcium is in constant exchange with the calcium of the extracellular fluid and bones. The parathyroid gland maintains the constancy of the calcium concentration in the plasma. The bones serve as a reservoir of calcium and phosphate to provide for the other needs of the body and supply minerals for deposition in the skeleton.

bone, cancellous (spongy bone, supporting bone, trabecular bone),

n the bone that forms a trabecular network, surrounds marrow spaces that may contain either fatty or hematopoietic tissue, lies subjacent to the cortical bone, and makes up the main portion of a bone.

bone, cancellous, atrophy of disuse

n the wasting of bone tissue occurring with loss of function of a part (e.g., a tooth). The supporting bone assumes an osteoporotic nature, and the marrow remains fatty or hematopoietic.

bone cells,

n.pl the group includes osteoblasts, osteocytes, osteoclasts, and osteoprogenitor cells.

bone changes, mechanical factors,

n.pl the pressure and tension forces that play an important role in determining bone structure. Improperly controlled appliances can resorb bone faster than deposition can occur, causing mobile teeth and traumatic occlusion. Poor vascularity is a concomitant cause of undue pressure and tension and may inhibit repair and cause necrosis.

bone chips,

n.pl the small pieces of cancellous bone generally used to fill in bony defects and precipitate recalcification.

n damage to the bones of adults is most often seen after heavy and localized radiation treatment.

bone, endochondral

n a bone that is developed in relation to antecedent cartilages (e.g., long bones, mandible). See also bone, intramembranous.

bone, endochondral, formation,

n a replacement of previously formed embryonic cartilage with an adult bony structure. The actual replacement of cartilage by bone is only part of the process, however; much of the bone is laid down directly external to the embryonic cartilage. See also bone, membrane, formation.

bone formation,

n the deposition of an organic mucopolysaccharide matrix (osteoid) that is subsequently mineralized with calcium salts. See also bone apposition and bone deposition.

n an osteotomy into or near the crest of the alveolar ridge for placement of an endosteal blade type of implant.

bone groove, canted,

n an osteotomy sloped to avoid the mandibular canal or keep the implant infrastructure within the medullary confines.

bone, horizontal loss of,

n a resorption of bone caused by periodontal inflammation in which the bone crest remains even with the cementoenamel junctions of two adjoining teeth. The condition may be localized or generalized.

Horizontal bone loss.

bone, internal reconstruction of,

n the formation of bone on the tensional side of the periodontal ligament with concurrent resorption from the marrow space; contralaterally, resorption of alveolar bone with apposition from the endosteum in the marrow space.

bone, interproximal,

n the bone that forms the septa between the teeth; consists primarily of a spongy supporting bone covered by a layer of cortical bone. See also septum, interdental.

bone, intramembranous,

n a bone developed within a membrane but having no associated cartilage (e.g., parietal, frontal, bones of upper face). See also bone, endochondral.

bone, intramembranous, formation,

n membrane bone forms directly from the mesenchyme, first as a thin, flattened, irregular bony plate or membrane in the dermis and gradually expanding at its margins and becoming thickened by the deposition of successive layers of additional bone on the inner and outer surfaces. See also bone, endochondral, formation.

bone involvement,

n changes in the alveolar and supporting bone occurring as a sequel to or accompanying inflammatory or dystrophic disease; usually of a resorptive nature.

n the small, fragile, paired facial bone that helps form a part of the orbital wall and also a small part of the nasal cavity. The bone has four borders and two surfaces that articulate with four other facial bones.

bone lamella,

n bone having the appearance of layers of thin leaves or plates. This appearance is produced by lines representing periods of inactivity of bone formation.

bone, malar (zygomatic bone), frontal process of,

n a prominence on the zygomatic bone (cheekbone) that forms the anterior lateral orbital wall.

n a prominence on the zygomatic bone (cheekbone) that forms part of the inferior rim of the orbit and a small part of the orbital wall.

n a prominence on the inferior aspect of the zygomatic bone (cheekbone) that articulates with the zygomatic process of temporal bone to form the zygomatic arch.

n the transplantation of bone marrow from healthy donors to stimulate production of formed blood cells. It is used in treatment of hematopoietic or lymphoreticular diseases such as aplastic anemia, leukemia, immune deficiency syndromes, and acute radiation syndrome.

bone membranes,

n.pl the membrane structures associated with the growth, development, and repair of bone. They include the periosteum, a connective tissue layer adjacent to bone surfaces; periodontal ligament, a modified periosteum associated with tooth structure; and endosteum, a thin layer of connective tissue lining the walls of the bone marrow spaces.

bone, microscopic appearance of,

n the composition of bone tissue as viewed under a microscope. Microscopically, bone is composed of osteocytes embedded within lacunae in a calcified intercellular matrix. Extending from the lacunae are small canals called canaliculi, which communicate with canaliculi of adjacent lacunae. Through this system of canals, nutrient material reaches the osteocytes and provides avenues for the removal of waste products of metabolism. It is deposited in incremental layers (lamellae) around haversian canals, the lamellae toward the surface of the bone being more or less parallel to it.

bone mineral content, chemistry of,

n the hardness of bone results from its mineral content in the organic matrix. The minerals (commonly designated as bone salts) and the organic matrix make up the interstitial substance of bone. The bone salts consist essentially of hydroxyapatite (Ca10[PO4]6[OH2]), carbon dioxide, and water, with small amounts of other ions.

n bone that is deposited in concentric layers around the long shaft of the bone in a manner similar to that of the growth of endochondral bone.

bone, physical properties of,

n a compact bone has the following physical characteristics: specific gravity, 1.92 to 1.99; tensile strength, 13,000 to 17,000 psi; compressive strength, 18,000 to 24,000 psi; compressive strength parallel to the long axis, 7150 psi; compressive strength at right angles to the long axis, 10,800 psi. These physical characteristics make bone particularly suitable for carrying out its functions of weight bearing, leverage, and protection of vulnerable viscera.

bone rarefaction

n a decreased density of bone such as a decrease in weight per unit of volume.

n the widening of the crest of the alveolus, primarily on the buccal and lingual aspects, varying from a thick ledge to a “beading” of the bone margin; results in a more or less bulbous contour of the gingival tissue overlying it.

bone, trabecular

n See bone, cancellous.

bone, vertical loss of,

n a resorption of bone caused by periodontal inflammation and occlusal trauma in which the bone crest is below the cementoenamel junctions of two adjoining teeth. It can be localized (mainly) or generalized.

bone, vertical plates of the palatine,

n the thin, oblong-shaped bone with two surfaces and four borders. It helps to form the floor of the orbit, the outer wall of the nasal cavity, and several adjoining structures.

bone volume (mass), age-affecting,

n decreases that occur in human body bone mass after age 40. Diet and exercise may be contributing factors.

n a character and pattern of bone resulting from the interweaving of broad bands of bone.

bone(s), cranial,

n the eight bones that make up the skull and protect the brain and include the ethmoid, frontal, occipital, sphenoid, two parietal, and two temporal bones.

bone(s), facial,

n the 14 bones that include the mandible, maxilla, frontal bones, nasal bones, and zygoma. With the exception of the mandible, maxilla, and vomer bones, the bones of the face occur in pairs, thus accounting for facial symmetry. They provide the framework for the face, serve as entry points for the digestive and respiratory systems, and provide the attachments for the muscles controlling facial expression.

bone(s), horizontal plates of palatine,

n the bones that form the posterior part of the hard palate and consist of four borders and two surfaces.

bone

1. the hard, rigid form of connective tissue constituting most of the skeleton of most vertebrates, composed chiefly of an organic component of collagenous matrix and cells and a mineral component of calcium phosphate and other salts.

2. any distinct piece of the skeleton of the body. For a named list of bones see Table 10.

3. describes conformation, substance, thickness and quality of bone structure in an animal, e.g. an animal with good bone. See also osseous.

bone ash

analysis of the degree of mineralization of bone is done by an ash analysis in which the bone is heated at 600°C until there is no further weight loss.

has histological characteristics of both cartilage and bone; may develop in response to tensions from frequently changing directions.

bone clamp

strongly built, handheld, tong-like instrument with outcurving blades making a circle when closed for grasping a piece of bone shaft. The handles are ratcheted to give a firm grasp, and the faces of the blades have deep, crossways grooves.

compact bone

bone substance that is dense and noncancellous.

cortical bone

the compact bone of the shaft of a bone that surrounds the marrow cavity.

bone cyst

a discrete, grossly visible cavity, filled with fluid and often lined by a membrane. It may be located under cartilage (subchondral), be a single cavity (unicameral), filled with blood (aneurysmal) or contain epidermal cells (epidermoid).

one whose thickness is slight, sometimes consisting of only a thin layer of compact bone, or of two layers with intervening cancellated bone and marrow; usually curved rather than flat.

bone flour

finely ground bone used as a mineral supplement in animal feed to supply additional calcium and phosphorus. Needs to be properly sterilized.

bone fragility

the ease with which bone fractures depends to a large extent on the density of its compact bone, that is its degree of mineralization, which in turn depends on a number of factors including age, nutritional adequacy, state of pregnancy and lactation and exposure to weight bearing.

mature bone in which the collagen fibers are in an orderly layered arrangement producing lamellae.

laminar bone

the formation of bone by the periosteum in layers, sometimes more than one layer at a time, to supplement the diaphyseal expansion of the bone. Is marked in farm animals and large dogs, and serves to accommodate the skeleton to the very rapid growth of the musculature.

the intercellular component of bone. It includes collagen and amorphous ground substance consisting mostly of mucopolysaccharides (chondroitin sulfate).

bone meal

a product made from meatless bones which are crushed and sterilized. The bones are derived from boning plants and retail outlets. The bonemeal is used as stock feed, fertilizer and in a number of industries. Care is needed in its preparation and in the selection of the bones because of the high risk of transmitting diseases including anthrax, salmonellosis, tuberculosis. A coarse grade of bone flour (see above). Prohibited from being used as a feed in many countries as part of programs to control or prevent bovine spongiform encephalopathy.

membrane bone

bone that develops within a connective tissue membrane.

metaplastic bone

bone formed by connective tissue by redifferentiation of mesenchymal cells.

bone mineral

principally calcium and phosphorus but includes also magnesium and, to a lesser extent, potassium and fluorine. Consisting mainly of hydrated calcium phosphate (apatite) and calcium carbonate.

bone modeling

the sum of the activities of the endosteum and periosteum of bone to produce bone forms.

low density bone around the lacunae of bone which contains much amorphous mineral. In this form the mineral is labile and therefore important in the maintenance of calcium homeostasis.

periosteal bone

bone deposition by the periosteum in successive laminae; the bone formation in new bone and in a callus, beginning as fibrocellular tissue forming from the endosteum and periosteum, followed by calcification and bone formation.

Patient discussion about bone

Q. Is a bone tumor cancer? My son is 10 years old and his Doctor found a tumor on his bone in an x-ray he did to him. Is this cancer?

A. A bone tumor doesn't necessarily mean cancer. It could be a benign tumor and not a cancer one. Your son's doctor may then obtain a biopsy sample of the tumor. This involves taking a small sample of the tumor that can be examined in the laboratory to determine what kind of tumor it is. The biopsy can be obtained either through a small needle (needle biopsy) or through a small incision (incisional biopsy).

Q. is bone loss related to Arthritis?

A. It depends on the kind of arthritis. In some arthritic diseases there's local bone loss, and generalized bone loss (osteoporosis) may result from steroids used to treat arthritic diseases.

You may read more here:www.nlm.nih.gov/medlineplus/osteoporosis.html

Q. I have constant pain on my feet more on my bones than anything,do I have arthritis? I do already have plantar fascictis

A. Chronic arthritis is a disease of the elderly and it isn't common to suffer from it in young age, however joint pain or bone pain can be caused by several other reasons, that might not be chronic, such as an infection, excessive physical activity or such. You should see a doctor to evaluate the pain and joint movement. He/ she might send you to do an x-ray to see if there's something they can see that is wrong with the joint or bone (dislocation or fracture).

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